Controlling device for jet-impelled water turbines



Nov. 30 1926. V 1,608,565

P. H. PITMAN GON'I'ROIQDING DEVICE FOR JET IMPELLED WATER TURBINES FiledSept. 15. 1926 2 Sheets-Sheet l i P z cq 4 2 1R1 .1.5.4 a j z I 1 WW7?Nov. 30 19 6. I 1,608,565

P. H. PITMAN CONTROLLING DEVICE FOR JET IMPELLEP WATER TURBINES FiledSept. 15 1926 2 Sheets-Sheet 2 Patented Nov. 30, 1926.

ED STATES OFF [C E.

PERCY HECTOR IITMAN, OF LONDON, ENGLAND;

CONTROLLING DEVICE FOR JET-IMiBELLED WATER TURBINES.

Application filedseptember 15, 1926, Serial No. 135,669, and in GreatBritain April 7, 1925.

This invention relates to the controlling devices of impulse turbines ofthe Pelton wheel type ofthe kind provided with a jet deflector and hasfor its object improvements in the" construction thereof whereby thesame can be operated with a minimum of power and efficient governing canbe obtained.

Controlling devices of the kind referred to, as heretofore constructed,have employed a deflector consisting of an inclined plate carriedbypivotedarms connected to a governor by which the said plate was causedto enter the jetso as to divert a suitable proportion of the water fromthe blades of the turbinewhile the supply was being gradual- 1ycurtailed in order to maintain the desired speed under differentconditions of load;

Owing to the resistance to be overcome when. a deflector of the kindreferred to is inserted into a high pressure jet considerable energy wasrequired to actuate it and this necessitatedin the case of large unitsthe employment of auxiliary apparatus which delayed its controllingaction and rendered the governing less sensitive and ineflicient.

In order to overcome the foregoing difficulties'the present inventioncomprises a balanced deflector that is acted upon by the jet at twopoints in such a way as to tend to turn. it in opposite directions aboutits point of support. As the forces applied at these points aresubstantially equal they balance each other with the result that aminimum effort is required to turn the improved deflector.

In some cases the improvedwdeflector is coupled to a needle valve thatcontrols the diameter of thewater jet. For this purpose the needle orspearisiprovided withmeans of :retarding: its movement in the directionto out oft 'thewater supply (so. as to avoid nalledon v trunnionbearings. is supported coaxially with the jet, which, when the turbineis running. with a full load passes centrally through the bore of thedeflector.

When the deflector is turned in its bearings 'oneside of its outersurface at the end nearest the nozzle and the other side ofits innersurface at its opposite end are brought into contact with the jet so asto deflect more or less of the water. away from the buckets of theturbine according to the angle through which the deflector is turned.The contour ofthe inner and outer surfaces of the deflectors are of suchconfiguration that the tendency of the jet to turn the deflector inronedirection by reason of its impinging against one end is counteracted bythetendency to turn it in the opposite direction by reason of theimpingement ofthe said jet against the opposite end of the deflector.

The deflector may be operated by a hand lever mounted on or connected toone of its trunnions by suitable linkage or it may be operated by a handwheel or a governor suitably connected to an arm secured to thedeflector, This linkage may also impart longitudinal movement to thespear of a jet-controlling valve through a spring.

In order to prevent the too-rapid closing of the valve the spear isprovided with a dash-pot or oil cylinder and has two shoul ders betweenwhich is situated a sleeve con nectedto a lever, hand wheel or governorthrough the aforesaid linkage. A spring is situated between the forwardend of the sleeve andthe shoulder on that side so that when the linkageis operated in the direction to close the valve the spring will becompressed and will slowly urge the spear forward at a speed controlledby the dashp Then the movement'is in the opposite direction the sleevewill directly engage the rear shoulder and immediately withdraw thespear to the extent determined by its operating means.

I will now describe my invention more particularly with the aid oftheaccompanying. diagrammatic drawings in which *ig. 1' shows in verticalsection one embodimentof the improved deflector and controlling gear inthe-full load position, as applied to a Pelton wheel,

Fig. 2 is a similar view showing the parts in theirrespective positionsafter the load has beenremoved,

Fig. 3 is a-detail showing a similar view able device,

of the deflector in the position it takes up after the jet has beenreduced by the controlling valve to suit the reduced load,

Fig. 4 is a'plan view of the deflector and jet nozzle and Fig. 5 is afront view of the defiectorwhen in the full load position. 7

According to the construction shown in the drawings a represents thebuckets of a Pelton wheel and c the nozzle'by which a jet d of highpressure water is directed on to the said buckets so as to rotate thewheel and drive the turbine.

When the load is reduced the speed of the motor will increase unless therod 6 be moved in thedirection ot the arrow in ,Fig. 1 so as to in vethe parts towards the position shown in Fig. 2.

The rod 6 may be operated by a lever, iand wheel or any suitablegovernor through suitable linkage as hereinbetore statec.

The deflector f is of tubular form and is provided with trunnions gjournalled in bearings it (Big. l) formed integrally with or bolted tothe nozzle 0, When the said defiector is turned onits truiinions in thedirection indicated in Fig. 1 its inner surface 2' at its forward endwill deflect the jet d in a downwarddirection away from the bucket-s a,and the rear edge 7' of the deflector will cut into the said jet and sodivide it into two parts at and (Z v Darius this process the pressure ofthe jet (Z on the surface 2' will tend to turn the deflector in acountercloclm'ise direction'and the pressure of the jet (5 on the undersur face is or the said deflector which will tend to turn it iii aoloclzwise direction with an equal force that will counteract the effectoi the jet (Z on thesuriace 2 thus enabling the deflector to be actuatedwith a minimum 7 amount of energy.

in order to obtain a steady action of deflector the end or" the surfacesand edge j should not be too far from the point about which thedeflector turns and so as to the produce the necessary compensating liftat 3' V ;to slide on the spear-rod which is provided with two shouiderss tend a springer. The spear rod has a head a at one end thatco-operates with the aperture to in the nozzle 0 to regulate thean iountof water delivered .by

the jet and is guided by a bearing andp'asses out of the conduit ythrough the labyrinth packing a, a -glan-d or any othersuit the Theopposite extremity of the spear-rod 1" is connected to the plungerl ofan oil cylinder whose opposite ends are connected by a pipe 3 providedwith a valve 4: to regulate the speed at which the oil can betransferred from the front end of the cylinder to the 7 rear. Theplunger i is provided with one or more valves 5 which allows the oil topass freely through them from the back to the front of the cylinder whenthe spear-head v is moved in the direction to increase the area of theaperture 10. The deflector f is provided with a stop 7 that engages aprojection 7 formed on an adjacent part when the turbine is running withfull load.

in operation the slee e is moved in the of the cyl nder whi h may beadjusted by the valve 2;

So se-on the speed of the turbine has been induced by the smallerquantity of water deliverec to the buckets by the nozzle 0 V the rod 6will be moved automatically if a governor is employed or by hand, intherever a position in which the reduced et just escapes he edge of thesurface 2' and the edge of the deflector; This movement will result in aread ustment the jet controllin valve until a position is reached inwhich the aforesaid reiationsl ip is maintained. When the sleevey ismoved in' a rearward direction owing to an increase in the load, suchmovement is transmitted "directly through the shoulder 8 to thespearrod1j whose operation in hat direction is not re tarded by the oilin the cylinder2. fl claim: 7 f jj r 1. An improved. controlling devicefor impulse turbines comprising balanced tu bular jetdefiector'supported in bearings and formed on opposite sides of its boreand of the axis of said bearing with deflecting se direction until thedeflector f assumes direction to compress the spring'a when L-HEcylinder .Zcan be trans-1 ferred' through the pipe 3 to the rear endportions, said deflecting portions "being;

formed with cooperating surfaces to be operated upon bythe deflectedportions of said et, so that such action on one said deflecting portionwill counterbalance the action on the other said deflecting portion. H I

2. An improved controlling device for impulse turbines comprisingabalanced tu hula-r deflector throughthe bore of" the power etinormallypasses coaxially,

transverse bearings to support said defleotor, said deflector having twointercepting portions situated on opposite sides o'f' flthe bore of saiddefiectorandon oppositesides of the axis of said bearing and moved intoand out of said jet according to the direction and degree of movement ofsaid deflector in its bearing, said intercepting portions havingsurfaces against which the deflected portions of said jet impinge so asto tend to turn the deflector in reverse directions and means ofgradually inserting both intercepting portions into said jet at the sametime to deflect a portion of said jet away from the turbine buckets andto balance the turning moments produced by the jet impinging on theintercepting portions of the. deflector substantially as set forth.

3. An improved controlling device for impulse turbines comprising abalanced tubular deflector through the bore of which the power jetnormally passes coaxially, transverse hearings to support saiddeflector, said deflector having two intercepting portions situated onopposite sides of the bore of said deflector and on opposite sides ofthe. axis of said bearing and moved into and out of said jet accordingto the direction and degree of movement of said deflector in itsbearing, said intercepting portions having surfaces against which thedeflected portions of said jet impinge so as to tend to turn thedeflector in reverse directions, means of gradually inserting bothintercepting portions into said jet at the. same time to deflect aportion of said jet away from the turbine buckets and to balance theturning moments produced by the jet impinging on the interceptingportions of the deflector, a. jet controlling valve, a valve rod havingtwo fiXGCl shoulders thereon, a sliding collar between said shoulders, aspring between said collar and the forward shoulder, a lever connectedto said collar, a rod connected to said lever and to the deflectoractuating means and means of operating said rod, substantially as setforth.

4. An improved controlling device for impulse turbines comprising abalanced tubular deflector through the bore of which the power jetnormally passes coaxially, transverse hearings to support saiddeflector, said deflector having two intercepting portions situated onopposite sides of the bore of said deflector and on opposite sides ofthe axis of said bearing and moved int-o and out of said jet accordingto the direction and degree of movement of said defiector in itsbearing, said intercepting portions having surfaces against which thedeflected portions of said jet impinge so as to tend to turn thedeflector in reverse directions, means of gradually inserting bothintercepting portions into said jet at the same time to deflect aportion of said jet away from the-turbine. buckets and to balance theturning moments produced by the jet impinging on the interceptingportions of the deflector, a. jet controlling valve, a valve rod, aconical head at one end of said valve rod, a plunger connected to saidrod, a cylinder in which said plunger is adapted to slide, fluid in saidcylinder, a valve in said plunger to permit said fluid to pass in onedirection, a channel to allow said fluid to pass from one end of saidcylinder to the other in the opposite direction, a valve in said channelto adjust the speed at which said fluid passes, two fixed shoulders onsaid valve rod, a sliding collar between said shoulders, a springbetween said collar and the forward shoulder, a lever connected to saidcollar, a rod connected to said lever and to the deflector actuatingmeans and means of operating said rod, substantially as set forth.

In testimonyrwhereof, I have signed my name to this specification at 61and 62 Chancery Lane, in the county of London, England, this 3rd day ofSeptember, 1926.

PERCY HECTOR PITMAN.

